关键词: 氧化物弥散强化钢, 弥散颗粒, 辐照

Abstract: Dispersoids in recrystallized PM2000 steel before and after irradiation were investigated by means of transmission electron microscope, selected area electron diffraction and energy-dispersive spectroscope. The results indicate that the number of dispersoids in the PM2000 steel significantly increases after irradiation, with the number density of dispersoids rising from 2.7×10²¹ m^-3 to 6.6×10²¹ m^-3. Irradiation does not significantly affect the size distribution and morphological characteristics of the dispersoids. In both unirradiated and irradiated PM2000 specimens, the majority of spherical particles with relatively small sizes is identified as YAlO₃ with a simple orthorhombic crystal structure, while a small number of larger particles is Al₂O₃. After irradiation, the chemical composition of Al-O and Y-Al-O phases in the PM2000 steel changes. After irradiation, the atom fraction of Al in Al-O phase decreases from an average of 32.5% to 24.5%, while the atonn fruction of O increases from 23.3% to 39.4%, showing that the content of oxygen increases significantly, and the content of aluminum relatively decreases. Meanwhile, the atom fraction of Al and Y in the Y-Al-O phase becomes 14.6% and 16.4%, respectively, indicating a decrease in both Al and Y content within the dispersoids. This phenomenon is attributed to the irradiation-induced diffusion of Al and Y atoms from the dispersoids into the matrix.

Key words: oxide dispersion strengthened steel, dispersed particles, irradiation